Harvesting winter canola in Kansas

Wednesday

May 15, 2013 at 12:01 AM

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Kansas State

Because of the cooler temperatures so far this spring, weanticipate canola harvest falling in mid-June in 2013. It is time now to startmaking plans for getting the crop out of the field. When making a plan andevaluating options, it is helpful to review some general principles.

General canola harvest guidelines

• Seed moisture should be 8 to 10% at harvest.

• Seed moisture can change rapidly, going from toowet to dry in a short period of time (a day or two or even several hours ifconditions are right).

• Seed moisture for canola is more critical forcontrolling shatter and reducing spoilage than for wheat.

• Canola is an indeterminate crop and will havesome immature pods and seeds when it is ripe for direct harvesting.

• Ripe canola must be harvested as soon aspossible to prevent shattering.

• Combine speed is slower for canola than forwheat.

• Cylinder speeds are typically 450 to 650 rpm.Concave clearance should be 3/4" in the front and 1/8" to 1/4" in the rear. Fanspeeds are similar to wheat.

• Refer to your combine manual for a startingpoint. If there is not a listing for canola, there should be one for rapeseed.Make adjustments according to what is coming into the bin and leaving the backof the combine.

Harvesting methods

There are four primary methods for harvesting winter canola:

1. Direct combining

2. Swathing followed by combining

3. Pushing followed by combining

4. Use of desiccants followed by combining.

The preferred harvest method depends on weather and cropconditions, the ability to harvest quickly, and equipment availability. In allcases, it is important to set the combine properly and monitor operationsfrequently, adjusting for changing moisture conditions. The primary concernswhen harvesting winter canola are to minimize seed loss and to harvest atmoisture levels that allow for proper seed storage and handling. It can bedifficult to dry down canola because the small seed restricts air movement, somake sure the crop is harvested at the proper moisture content.

Direct combining

Winter canola can be direct combined under the rightconditions. A few general rules apply to combine set up and operation:

Cut just below the seedpods, typically 12" or more above the ground. Reel speed should match ground speed. Operating the reel too fast will cause pod shatter. The seed is ready to harvest before the entire plant is brown; the lower stem will remain green. Use a handheld grain tester to check moisture levels. In thinner stands it is not unusual to have some green pods due to branching and uneven maturity. These green pods will pass through a properly set combine. Set your combine to crack the mature pods but not break them up too much. Keep the air speed down so that seed does not blow out the back of the combine. At this setting the green pods should not crack and will flow out the back of the combine. Keeping green pods from breaking open will reduce green seed count and keep grain moisture content low.

There are several advantages to direct combining:

Works well for uniform, tall, interlaced, thick stands. Works better than other methods under hot and dry conditions. Generally results in the best overall yield and quality because the crop is allowed to ripen completely. Seed is only handled once as compared to swathing or pushing prior to harvest. Lower harvesting costs because no additional machinery is needed.

There are also some disadvantages to direct combining:

Must harvest when crop is ready, perhaps interrupting wheat harvest. For producers with large acreages, winter canola may not be able to be harvested in a timely manner, thus increasing the risk for shattering losses. If relying upon custom cutters, they must be there when the crop is ready and be willing to harvest the crop in a timely fashion. Thin stands can result in uneven plant maturity. Standing canola is more susceptible to seed loss from heavy rain, hail, and high winds.

Swathing

There are circumstances where swathing is the best option.The key to minimizing harvest losses with this method is swathing at theappropriate crop stage in a timely manner. The optimum time to swath wintercanola is when average seed color change on the main stem is 40 to 60% and theseed contains 30 to 40% moisture. The decision to swath should be made based onseed color change and not pod color change. Make sure you open the pods andlook at the seed and not just the pod itself. The appearance of the pod willmore than likely be yellowish-green and the seed will be brown inside. Seedcolor change occurs rapidly, about 10% change every 2-3 days. Swathing lateincreases the potential for shattering losses. Swathing too early increases thechances for high green seed count. Windrows will be harvested using a pickupheader.

Here are a few general rules to swathing:

Start monitoring crop stage about one week after flowering. Continue to monitor for proper stage every 2-3 days following. Seed color is the key for determining when to swath, not overall plant or pod color! Use a draper, belt-style swather. Do not crimp the windrow! Try to avoid swathing during the heat of the day (over 85 degrees F). This prevents accelerated seed curing and reduces the potential for high green seed count. Swath just below the lowest pods. Windrows should not be placed directly on the ground, but on top of standing stubble several inches above the ground. This allows for air circulation around the windrow. A roller attachment can be used to push the windrow into the standing stubble, further protecting it from the weather. The crop can be in windrows for 7 to 10 days. If conditions are hot, dry, and windy, then it may be closer to 4 days.

There are several advantages to swathing:

Typically earlier harvest because drydown is accelerated by cutting off the plant. Better ability to manage large acreages of canola. With earlier harvest, it may increase doublecropping opportunities by a week or more. Helps dry up any weeds present in the field that might increase seed moisture content. Proper swathing with good, tight windrows can withstand heavy rain and winds with minimal yield loss. Helps control uneven maturities in fields. Fewer risks associated with severe weather than with direct combining.

There are also disadvantages to swathing:

Potential for yield loss from cutting off the plant prematurely when swathed prior to the optimum stage. Potential for yield loss from shatter when swathed later than the optimum stage. Swathing during hot, dry conditions (over 85 degrees F) can result in seed shrinkage. More time, investment, and labor involved. Tall, tangled, or lodged stands can be difficult to swath. If not placed properly into standing stubble, strong winds can move windrows.

Pushing

Pushing was developed in Canada as an alternative toswathing. It is designed to provide the advantages of direct combining whileminimizing some of the risks associated with direct combining or swathing.

A pusher is a roller hydraulically mounted on the front of atractor which is driven at high speeds through the field. The pusher forcelodges, or "pushes," the crop over without cutting the plants off from the rootsystem. The concept is to prevent yield losses from weather events by layingthe crop over, allowing the crop to mature normally. Vertical sickles arelocated at both ends of the pusher/roller and directly in front of the tractortires. These are designed to ensure a clean cut between passes and reduce theamount of canola crushed by the tires. Once the canola is ripe, it can becombined in the opposite direction it was pushed. The header width of thecombine should match the width of the pusher. Harvesting is typically slowerthan direct combining and swathing due to the amount of material entering thecombine.

There are advantages to pushing:

Reduces susceptibility to shattering from wind and storms. Allows the crop to ripen completely. Works well in fields with high yield potential and heavy, thick stands. Works well for tall canola crops.

There also are disadvantages to pushing:

Shorter, thinner crops do not push well. Pushing equipment is currently scarce in Kansas. Pushing is still a new concept in the southern Great Plains, so experience is limited.

Desiccants

Desiccants are now labeled for use in Kansasand Oklahoma.There are two products available: Reglone Desiccant (diquat dibromide) fromSyngenta and Nufarm Diquat SPC 2 L (generic diquat). Desiccants are generallynot necessary under normal growing conditions. However, over the past couple of years, situations where desiccants maybe of benefit have arisen. Desiccants should be applied at 85% seed colorchange. Growers should not desiccate and then try to swath or push a crop.

Producers may consider using a desiccant under the followingconditions:

Heavy weed infestations caused by thin stands. Excessive lodging, making it harder to push and swath. Uneven crop maturity due to thin stands, low spots, wet holes, sandy knobs, or excessive rainfall making it harder to push or swath.

Summary

Canola producers have a several avenues to assist them withcanola harvest and getting their crop out of the field in a timely fashion. Oklahoma State Universityhas created a list of available custom harvesters, swathers, and pushers. It isavailable at: www.canola.okstate.edu/index.htm.

Look for the new K-State publication MF-3092, Harvest Management of Canola, availableat: http://www.ksre.ksu.edu/bookstore/pubs/MF3092.pdf

Whatever harvest method you choose, the key to success isplanning ahead and performing all operations in a timely manner!

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